1) To make obtaining this and all other achievements faster go to options and turn speed play on
2) Custom play -> Duplicate -> Two players -> select location (no need to change default location, it is just waste of time)
3) Select human for player 2
4) With player 1 (you) roll dices once and select square with most points.
5) With player 2 roll dices once and select square with “-“ mark or lowest points.
6) Continue until you finish the game and you can start new one right away.
Same method works for all these achievements, you just need to change game mode:
Rainbow master
Classic master
Classic Sensei
Rainbow sensei
Duplicate sensei